Re: [PATCH v2 1/1] mm: Always release pages to the buddy allocator in memblock_free_late().

[Ingo Molnar]

* Aaron Thompson <dev@xxxxxxxxxx> wrote:

> 
> On 2023-01-05 02:48, Ingo Molnar wrote:
> > * Aaron Thompson <dev@xxxxxxxxxx> wrote:
> > 
> > > For example, on an Amazon EC2 t3.micro VM (1 GB) booting via EFI:
> > > 
> > > v6.2-rc2:
> > >   # grep -E 'Node|spanned|present|managed' /proc/zoneinfo
> > >   Node 0, zone      DMA
> > >           spanned  4095
> > >           present  3999
> > >           managed  3840
> > >   Node 0, zone    DMA32
> > >           spanned  246652
> > >           present  245868
> > >           managed  178867
> > > 
> > > v6.2-rc2 + patch:
> > >   # grep -E 'Node|spanned|present|managed' /proc/zoneinfo
> > >   Node 0, zone      DMA
> > >           spanned  4095
> > >           present  3999
> > >           managed  3840
> > >   Node 0, zone    DMA32
> > >           spanned  246652
> > >           present  245868
> > >           managed  222816   # +43,949 pages
> > 
> > [ Note the annotation I added to the output - might be useful in the
> > changelog too. ]
> > 
> > So this patch adds around +17% of RAM to this 1 GB virtual system? That
> > looks rather significant ...
> > 
> > Thanks,
> > 
> > 	Ingo
> 
> It is significant, but I wouldn't describe it as being added. I would say
> that the system is currently losing 17% of RAM due to a bug, and this patch
> fixes that bug.

To the end-user gaining +17% [or +3%] extra usable RAM compared to what 
they had before is what matters, and it's a big deal. :-)

Thanks,

	Ingo